2008/09/01 by Nathan Smith · 2 citations
Physics and Astronomy · #Gamma-ray bursts and supernovae #Pulsars and Gravitational Waves Research #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1038/nature07269
published as 2008, Nature, 455, 201 · 10 pages, 3 color figs, supplementary information. Accepted by Nature
openalex publication_date 2008/09/01 · arxiv created 2008/09/09 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/29
Very massive stars shed much of their mass in violent precursor eruptions as luminous blue variables (LBVs) before reaching their most likely end as supernovae, but the cause of LBV eruptions is unknown. The 19th century eruption of Eta Carinae, the prototype of these events, ejected about 12 solar masses at speeds of 650 km/s, with a kinetic energy of almost 1050 ergs. Some faster material with speeds up to 1000-2000 km/s had previously been reported but its full distribution was unknown. Here I report observations of much faster material with speeds up to 3500-6000 km/s, reaching farther from the star than the fastest material in earlier reports. This fast material roughly doubles the kinetic energy of the 19th century event, and suggests that it released a blast wave now propagating ahead of the massive ejecta. Thus, Eta Car's outer shell now mimics a low-energy supernova remnant. The eruption has usually been discussed in terms of an extreme wind driven by the star's luminosity, but fast material reported here suggests that it was powered by a deep-seated explosion rivalling a supernova, perhaps triggered by the pulsational pair instability. This may alter interpretations of similar events seen in other galaxies.